Due to diminishing quantities of coal, petroleum, and natural gas products, attention is being directed to other energy sources, including oil shale, solar energy, and nuclear energy. One source receiving considerable attention is biomass materials such as wood and its byproducts. Biomass has the potential for use in countless different applications including generating heat, production of liquid fuel, production of biogas, generating bioelectricity, and production of feedstock for chemicals and other materials.
Forest biomass includes any type of biomass produced by forest growth such as dead trees, non-merchantable trees, branches, understory, tree stumps, interplanted crops, other plants, clippings, logging residue, stems, wood chips, or other similar material. Forest biomass often contains undesirable material such as bark, silt, leaves, sand, needles, and dirt, which may cause problems during further processing. For example, in one type of heating and power application, biomass is typically densified (e.g., formed into pellets or briquettes) for burning in stoves. Sand and dirt in the biomass may reduce the service life of chipper components and pelletizing dies used in the densification process. Additionally low bark content is generally preferred for densification processes in order to minimize ash content.
The presence of undesirable materials may also cause problems in other biomass applications. Cellulosic ethanol, for example, is a type of biofuel which can be produced using either biochemical or thermochemical techniques. Regardless of which approach is used, the presence of dirt, silt, and other non-cellulosic materials may reduce the effectiveness of the process.
In addition to the examples discussed above, there are a number of other biomass applications in which the presence of undesirable materials may pose challenges. Thus, cleaning and conditioning biomass may be useful in many applications. As technologies for utilizing biomass become more sophisticated, the number and value of potential applications continues to grow. Thus, there is a need to develop a biomass conditioning system and methods for conditioning biomass to remove undesirable material in preparation for further processing.